1. Technical Field
Example embodiments of the present invention relate in general to a transmission and reception apparatus and method, and more particularly, to an adaptive coding modulation (ACM)-based simulcast transmission and reception apparatus and method.
2. Related Art
On the basis of existing satellite-based digital broadcasting and wideband Internet service technology, a broadcasting and telecommunication convergence service enabling reception of broadcasting and communication at any time in any place according to the concept of a ubiquitous network has recently come into the limelight. Due to such an environment, active efforts are being made to ensure competitiveness by improving service quality in the international and domestic satellite broadcasting field, and a high-quality satellite broadcasting service employing digital video broadcasting-satellite second generation (DVB-S2), which is highly efficient satellite transmission technology, and H.264 video compression technology, which offers remarkable performance, is emerging. Also, as a 21 GHz Ka frequency band having a wide band of 600 MHz becomes usable for broadcasting-satellite service (BSS) in Region 1 and Region 3, satellite broadcasting for providing a multi-channel high-quality high-definition television (HDTV) service will further progress.
However, unlike the Ku band that has been widely used as an existing satellite broadcasting service band, the Ka band is very vulnerable to rain, and has a serious problem of signal attenuation caused by rain in comparison with other bands. To solve this problem, link power control, a diversity scheme, a beamforming technique, a hierarchical transmission scheme, an ACM technique, etc. are used.
Among these techniques, the hierarchical transmission technique involves transmitting an image signal through multiple bands. A high-quality image signal to which a high-order modulation scheme and a high coding rate are applied is transmitted through one of the multiple bands, and a lower-quality image signal to which a low-order modulation scheme and a low coding rate are applied is transmitted through another of the multiple bands. Since the high-quality image signal and the low-quality image signal that can be received in the rain are simultaneously transmitted through the multiple bands, it is possible to prevent signal attenuation caused by rain. However, the high-quality image signal and the low-quality image signal are transmitted together through multiple bands even in a non-raining region in which transmission of the low-quality image signal is unnecessary, and thus a bandwidth is not efficiently used.